Purpose <p>This article used potassium feldspar as raw material, with KOH and NaOH as additives for low-temperature roasting, to explore the extraction law and reaction mechanism of SiO₂ and prepare molecular sieves with different morphology and structure.</p> Methods <p>This article used the roasting method to activate potassium feldspar, extract the silicon source, and determine the roasting mechanism through kinetic experiments. Under the optimal conditions, the molecular sieves were successfully prepared by hydrothermal method. The specific surface area, pore volume, and hygroscopic performance of the two molecular sieves were compared.</p> Results <p>The moisture absorption performance of molecular sieve prepared by using sodium hydroxide to activate potassium feldspar at low temperature is better than that of molecular sieve prepared by using potassium hydroxide as additive.</p> Conclusions <p>In this study, NaOH was used as an additive to activate potassium feldspar and prepare high-value-added molecular sieves, which can reduce the preparation cost of molecular sieves, improve economic benefits, and comprehensively utilize potassium feldspar resources.</p>